A hemostat or forceps is a simple pliers-like tool that uses mechanical action between its jaws to constrict vessels and is commonly used in open surgical procedures to grasp, dissect and/or clamp tissue. Electrosurgical forceps utilize both mechanical clamping action and electrical energy to affect hemostasis by heating the tissue and blood vessels to coagulate, cauterize and/or seal tissue.
Over the last several decades, more and more surgeons are replacing traditional open methods of gaining access to vital organs and body cavities with endoscopes and endoscopic/laparoscopic techniques and instruments that access organs through small puncture-like incisions. Endoscopic instruments are inserted into the patient through a cannula, or port that has been made with a trocar. Typical sizes for cannulae range from three millimeters to twelve millimeters. Smaller cannulae are usually preferred, which, as can be appreciated, ultimately presents a design challenge to instrument manufacturers who must find ways to make surgical instruments that fit through the cannulae.
By utilizing an electrosurgical instrument, a surgeon can cauterize, coagulate/desiccate and/or simply reduce or slow bleeding, by controlling the intensity, frequency and duration of the electrosurgical energy applied through the jaw members to the tissue. Typically, electrodes, housed in each of the jaw members are charged to a different electric potential such that when the jaw members grasp tissue, electrical energy can be selectively transferred from one electrode to the other and through the tissue.
Bipolar electrosurgical instruments are known in the art. Commonly-owned U.S. Patent Application Publication No. 2007-0062017, discloses an exemplary bipolar electrosurgical instrument. Conventional bipolar electrosurgical instruments may include a cutting blade, fluid applicator, stapling mechanism or other like feature, in various combinations.
During certain procedures, surgeons must identify certain anatomical structures such as large vasculature, bile ducts, or urinary ducts such as the ureter. These structures often need to be avoided or in some instances ligated during a procedure, thus requiring a high degree of confidence when identifying such structures so that they can be properly avoided or ligated as the situation may merit. In surgery (open or laparoscopic), the surgeon is constantly relating the visualized anatomy they are currently operating on or near to known text book anatomy. This task is most difficult when the target anatomy (or that to be avoided) is obscured by overlying soft tissue. As such, the ability to ‘see’ what lies below the visual tissue surface is desired.
One issue during laparoscopic procedures in particular, is inadvertently injuring nearby critical anatomical structures due to quick or abrupt movement of instruments within the surgical site, poor visibility, lack of tactile response, confusion of the anatomy from patient to patient, or inadequate control of the instrumentation being utilized to perform the procedure. For example, when performing a laparoscopic cholecystectomy to remove the gallbladder, a particular aspect of the procedure is the identification of the common bile duct.
Similarly, when conducting procedures in the lower abdomen such as hernia repair or hysterectomies, great care should be taken to identify the ureter that connects the kidneys to the patient's bladder. Unfortunately, the ureter is at times obscured by connective tissue, and difficult to identify. These issues associated with identifying relatively small lumen (e.g. ureter, blood vessels, gall ducts, etc.) which at times are located proximal other similarly looking lumen are well known and systems have been devised to address them.
For example, there are several systems which employ the use of a stent or catheter to be placed internal to the structure being identified. Some of these systems utilize a light generator which illuminates the lumen. The illumination can be in the visible spectrum for the doctor to easily recognize or in the infrared (IR) spectrum such that it can be detected using an IR camera. The light, in either event, is received by a camera and the doctor is able to visualize the location of the lumen in question.
Another example of known devices employs a long stent placed into the ureter and extending from the bladder to the kidneys. Using a signal generator, the stent is electrified and produces an electrical field. The cutting or grasping surgical instrument used in the underlying surgical procedure includes one or more sensors which can detect the electrical field and signal an alarm if the cutting or grasping device comes too close to the lumen.
These known systems have several significant drawbacks. The first is that they each require a specialized stent or catheter to be placed within and along the length of the lumen being detected. As a result, use of such devices requires a special surgeon to be employed in the mere placement of the stent or catheter. The placement in such delicate structures is quite difficult and time consuming. The use of an additional surgeon, one who likely is not otherwise involved in the underlying procedure being performed, significantly increases the cost of the procedure being performed. Further the placement is time consuming and thus increases the overall operating time for the patient. Again this increases the costs of the procedure, as well as increasing the time the patient must be sedated. With respect specifically to the detection of the ureter, placement of the stent or catheter can be quite problematic.
Other known systems for detecting structures within the body employ the use of fluorescent dyes or other marker materials, such as radioactive fluids which can be used to detect the location of the desired structure within the body. Again there are shortcomings associated with these systems. The dyes employed often are not detectable through tissue, that is they cannot be easily detected from outside the lumen and are better employed in detecting cysts and polyps within a lumen as is common. Radioactive markers are also used to identify structures within a lumen using often x-ray and other visualization techniques. However, these visualization techniques are often not conveniently useable to identify structures while the surgical procedures described above are on-going.
Yet a further known technique is the use of ultrasound imaging to provide clinicians the ability to image sub-surface structures. Ultrasound imaging relies on different acoustic impedances of adjacent tissue structures to provide the contrast required for imaging—usually without the addition of exogenous contrast agents, though these may be employed to identify particular structures. Current techniques include imaging prior to surgery with a trans-cutaneous probe or in the surgical field with a laparoscopic probe. Ultrasound imaging possesses several key advantages over other modes of imaging (e.g., CT, MRI, etc.) which make it very attractive for real-time application in surgery.
The advantages of ultrasound imaging as compared to MRI and CT scans include the necessary hardware being relatively small and inexpensive. Further, the radiation levels imparted on the patient as well as clinicians is considered inherently safe which is not necessarily true for CT. Further, the data is collected instantly and at the point of use as opposed to requiring the patient be positioned in an imaging vessel.
A variety of modes of operation for ultrasound imaging have been developed over the years include A-Mode, B-Mode, M-Mode and Doppler. A-mode (amplitude mode) is the simplest type of ultrasound. A single transducer scans a line through the body with the echoes plotted on screen as a function of depth. In B-mode (brightness mode) ultrasound, a linear array of transducers simultaneously or sequentially scans a plane through the body that can be viewed as a two-dimensional image on screen. In M-mode (motion mode) ultrasound, a single scan line is repeatedly sampled in the same location. The brightness representation of each scan in time is drawn vertically either from left to right on screen or in a fixed location on screen with the older results shifting to the left in a trailing update mode. Over time, this is analogous to recording a video in ultrasound. As the organ boundaries that produce reflections move relative to the probe, this can be used to determine the velocity of specific organ structures. Doppler mode makes use of the Doppler Effect in measuring and visualizing blood flow. In general, whether employing Color Doppler, Power Doppler, or Pulsed Wave Doppler, by calculating the frequency shift of a particular sample volume, for example flow in an artery or a jet of blood flow over a heart valve, the speed of the fluid and its direction can be determined and visualized. In for example, Pulsed Wave Doppler, velocity information is presented as a color coded overlay on top of a B-mode image. Other modes and combinations of modes are also employed in ultrasound imaging, as will be appreciated by those skilled in this art.
There are however, disadvantages to current to ultrasound techniques, particularly the (laparoscopic approaches) which have limited its adoption in minimally invasive surgery. In some of these approaches the image is presented on a separate screen from the laparoscopic image, forcing the surgeon to mentally “shift gears” as they focus on the laparoscope image or the ultrasound image. Current 2-D or even 3-D imaging systems generally seek to provide the highest level of image detail. While this may be useful in the diagnostic phase of care, this is likely more information than is necessary in the real-time treatment venue of an operating room where the questions facing the surgeon are not “What's wrong?” but simply, “Where is it?” Still further in many surgical suites, the required ultrasound cart and probes are simply not available as the need for sub-surface imaging does not exist in every surgical case.
One drawback of current imaging systems is the size and cost of linear imaging arrays comprised of many small piezo electric elements. While they provide detailed images, these probes are costly to manufacture and bulky relative to the size of laparoscopic surgical devices. The present disclosure is directed to addressing these shortcomings of the current systems.